Frankly I don't think 32 is enough.
Above 3 screen
Middle 3 screen
Below 3 screen
When most sound images on screen often leave the screen they often have the sound panning along the stage to surrounds and often a lot of films I have watched and listened to don't sound correct enough to the on-screen to off-screen.
Point is there needs to be more and more for the surrounds or at least
Upper corner left and right (panning though) x4
Middle side wall left and right (panning though) x4
Below corner left and right (panning though) x4
Overhead surrounds x4 or more speakers are cheap least to me.
Below surround x4 spread around underneath my cinema seats so at least I can hear sound of rain landing on the floor to make me least at thing I'm standing outside. While rain drops land on tree leafs at different side wall arrays and above if standing underneath a tree. Rain is complex sound effect to convince me that the artificial fabricated sound to be realistic enough.
Upper corner left to right (panning though) x4
Middle wall left to right (panning though) x4
Below corner left to right (panning though) x4
FLFE.1 Front Low Frequency Effects,would be omnidirectional (can be summed up with multiples to create a uniform coverage)
RLFE.2 Rear Low Frequency Effects would be omnidirectional (can be summed up with multiples to create a uniform coverage)
55 I can fit that in my room.
The scene with the train from The Peacemaker where the train is cuff-puffing on screen centre and then moves off-screen the train on-screen exits the screen form below and would make some visual sense of the tunnel puffing the smoke up from below my cinema seats, then puffing on the rear back lower corner to the floor.